Air admittance valve

ABSTRACT

An air admittance valve which when subjected to a negative pressure condition vents a pipe system to an ambient environment. Generally, the air admittance valve includes a housing, a cartridge, and a sealing member. The housing includes one or more vents disposed in its wall and may be engaged with the pipe system at one end. The cartridge may have one or more inlets defining one or more inlet openings, where the one or more inlets are connected to a central chamber that has an opening with a sealing structure. The sealing member interacts with the sealing structure of the cartridge to allow one-way airflow from the central chamber to the pipe system. The cartridge and sealing member may be inserted into the housing such that the one or more inlet openings substantially align with the one or more vents in the housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/263,326, filed Apr. 28, 2014, which is incorporated by referenceherein in its entirety.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to air ventilation devices for use in pipesystems, and, more particularly, to air admittance valves used to ventpipe systems to the ambient environment.

BACKGROUND

In general, air admittance valves are used in plumbing systems as analternative to vent systems that require venting through a complicatedpipe system and/or rooftop vent system. Air admittance valves areone-way mechanical valves that may be located in a ventilated space toalleviate a need to connect to a central vertical vent (or to provide aseparate vertical vent) that passes through the roof of a structure. Airadmittance valves are normally closed, but open during a negativepressure condition, such as when wastewater is released. This allows airto enter the plumbing system and facilitate drainage. Once the flow ofthe wastewater ceases, the valve closes and remains closed until anothernegative pressure condition occurs. In such a manner, odors areprevented from escaping from the vent system.

Many air admittance valves are overly complex, have high part counts,and require expensive equipment and adhesives to assemble. There is aneed for an improved air admittance valve that is easier and lessexpensive to manufacture, and that provides better performance overprevious designs.

BRIEF SUMMARY OF THE INVENTION

Air admittance valves, such as for ventilating a plumbing system, aretherefore provided having an improved, cost effective design. In thisregard, an air admittance valve is provided that may be configured, whensubjected to a negative pressure condition, to vent a pipe system to anambient environment. In some embodiments, the air admittance valve mayinclude a housing having at least one vent disposed in a wall of thehousing. The housing may be configured to be engaged with the pipesystem at a first end.

In some embodiments, the air admittance valve may include a cartridgehaving at least one inlet defining at least one inlet opening. The atleast one inlet may be connected to a central chamber. The cartridge maydefine an opening of the central chamber having a sealing structure.

In some embodiments, the air admittance valve may include a sealingmember defining a sealing surface. The sealing member may be configuredto move between a closed position and an open position. The sealingsurface may be configured to interact with the sealing structure of thecartridge to allow one-way airflow from the central chamber to the pipesystem.

In some embodiments, the cartridge may be configured to be insertedwithin the housing, such that the at least one inlet opening may beconfigured to substantially align with the at least one vent in thehousing. In some embodiments, the cartridge may be removable such thatthe cartridge may be configured to be replaced without damaging ordisassembling the housing.

In some embodiments, the sealing member may further include a guideportion and the housing further defines a seal guide. The seal guide maybe configured to movably engage the guide portion.

In some embodiments, the air admittance valve may include at least onegasket configured to be disposed between the cartridge and the housingto prevent airflow from bypassing the inlet of the cartridge.

In some embodiments, the air admittance valve may include an internalcommunication wall configured to align the cartridge with an interior ofthe housing. The air admittance valve may define an end chamber betweenthe cartridge and a second end of the housing when the cartridge isdisposed within the housing. The internal communication wall may defineat least one opening such that the internal communication wall may beconfigured to fluidly connect the end chamber with the pipe system.

In some embodiments, the air admittance valve may include a central postwithin the central chamber configured to restrict the movement of thesealing member into the central chamber when subjected to a positivepressure from the pipe system.

Some embodiments of the air admittance valve may include a locatingfeature on the cartridge and a corresponding locating slot on thehousing configured to guide the cartridge into alignment with the atleast one vent during insertion of the cartridge into the housing. Someembodiments of the air admittance valve may include a positioningfeature on the cartridge and a corresponding positioning feature on thehousing configured to hold the cartridge in alignment with the at leastone vent after insertion of the cartridge into the housing.

In some embodiments, the cartridge of the air admittance valve mayinclude a duct wall that defines the central chamber in an interior ofthe duct wall. The cartridge may further include at least one inlet tubedefining the at least one inlet, such that the at least one inlet tubespans between the at least one vent of the housing and the duct wallwhen the cartridge is inserted within the housing. The air admittancevalve may define a void between the duct wall and an inner wall of thehousing in fluid communication with an end chamber and the pipe system.The void may only be in fluid communication with the inlet and centralchamber when the sealing member is in the open position. In someembodiments, the cartridge may define an inner duct wall and aconcentric outer duct wall. An interior of the inner duct wall maydefine the central chamber. The at least one inlet opening may bedefined in an outer surface of the outer duct wall and the at least oneinlet may connect the outer surface of the outer duct wall with thecentral chamber, such that the outer surface of the outer duct wall maybe in fluid communication with the central chamber. The air admittancevalve may define a void between the inner duct wall and the outer ductwall in fluid communication with an end chamber and the pipe system, andthe void may only be in fluid communication with the inlet and centralchamber when the sealing member is in the open position.

In some embodiments, the cartridge may define at least one curvedsurface configured to direct airflow from the at least one inlet towardthe sealing member. The at least one curved surface may be defined on abottom surface of the central chamber proximate the at least one inlet.

In another embodiment of the present invention, a cartridge may beprovided for an air admittance valve. The cartridge may include at leastone inlet defining at least one inlet opening. The at least one inletmay be connected to a central chamber, and an opening of the centralchamber may include a sealing structure. In some embodiments, thesealing structure of the cartridge may be configured to interact with asealing surface of a sealing member to allow one-way airflow from thecentral chamber to the pipe system. The cartridge may be configured tobe disposed within a housing having at least one vent, such that the atleast one inlet opening of the cartridge is configured to substantiallyalign with the at least one vent in the housing.

In some embodiments, the cartridge may include at least one gasketconfigured to be disposed between the cartridge and the housing toprevent airflow from bypassing the inlet of the cartridge. The cartridgemay include an internal communication wall configured to align thecartridge with an interior of the housing. In some embodiments, an endchamber may be defined between the cartridge and a second end of thehousing when the cartridge is disposed within the housing. The internalcommunication wall may define at least one opening such that theinternal communication wall may be configured to fluidly connect the endchamber with the pipe system.

In some embodiments, the cartridge may include a central post within thecentral chamber configured to restrict the movement of the sealingmember into the central chamber when subjected to a positive pressurefrom the pipe system.

Some embodiments of the cartridge may include a locating feature on thecartridge configured to engage a corresponding locating slot on thehousing and configured to guide the cartridge into alignment with the atleast one vent during insertion of the cartridge into the housing. Someembodiments of the cartridge may include a positioning feature on thecartridge configured to engage a corresponding positioning feature onthe housing and configured to hold the cartridge in alignment with theat least one vent after insertion of the cartridge into the housing.

In some embodiments, the cartridge includes a duct wall that defines thecentral chamber in an interior of the duct wall. The cartridge mayinclude at least one inlet tube defining the at least one inlet, suchthat the at least one inlet tube may be configured to span between theat least one vent of the housing and the duct wall when the cartridge isinserted within the housing. In some embodiments, the cartridge may beconfigured to define a void between the duct wall and an inner wall ofthe housing in fluid communication with an end chamber and the pipesystem when the cartridge is inserted into the housing. The void mayonly be in fluid communication with the inlet and central chamber whenthe sealing member is in the open position. In some embodiments, thecartridge may define an inner duct wall and a concentric outer ductwall, wherein an interior of the inner duct wall defines the centralchamber. The at least one inlet opening may be defined in an outersurface of the outer duct wall and the at least one inlet may connectthe outer surface of the outer duct wall with the central chamber, suchthat the outer surface of the outer duct wall may be in fluidcommunication with the central chamber. In some embodiments, thecartridge may define a void between the inner duct wall and the outerduct wall configured to be in fluid communication with an end chamberand the pipe system when the cartridge is inserted into the housing, andthe void may only be in fluid communication with the inlet and centralchamber when the sealing member is in the open position.

In some embodiments, the cartridge may define at least one curvedsurface configured to direct airflow from the at least one inlet towardthe sealing member. The at least one curved surface may be defined on abottom surface of the central chamber proximate the at least one inlet.

In yet another embodiment of the present invention, a method forassembling an air admittance valve is provided. The method may includeproviding a housing configured to engage a pipe system at a first endhaving at least one vent disposed in a wall of the housing. The methodmay include inserting a sealing member having a sealing surface into thehousing. In some embodiments, the method may include inserting acartridge having at least one inlet defining at least one inlet openinginto the housing, such that the at least one inlet opening substantiallyaligns with the at least one vent in the housing. The at least one inletmay be connected to a central chamber having an opening defining asealing structure. The sealing surface of the sealing member may beconfigured to interact with the sealing structure of the cartridge toallow one-way airflow from the central chamber to the pipe system.

In some embodiments, the sealing member may include a guide portion andthe housing further defines a seal guide. The seal guide may beconfigured to movably engage the guide portion.

In some embodiments, the method may include locating at least one gasketbetween the cartridge and the housing to prevent airflow from bypassingthe inlet of the cartridge.

In some embodiments, the cartridge may include an internal communicationwall configured to align the cartridge with an interior of the housing.In some embodiments, an end chamber may be defined between the cartridgeand a second end of the housing when the cartridge is disposed withinthe housing. The internal communication wall may define at least oneopening such that the internal communication wall may be configured tofluidly connect the end chamber with the pipe system.

In some embodiments, the cartridge may include a central post within thecentral chamber configured to restrict the movement of the sealingmember into the central chamber when subjected to a positive pressurefrom the pipe system.

In some embodiments, the cartridge may include a locating featureconfigured to engage a corresponding locating slot on the housing andconfigured to guide the cartridge into alignment with the at least onevent during insertion of the cartridge into the housing. In someembodiments, the cartridge may include a positioning feature configuredto engage a corresponding positioning feature on the housing andconfigured to hold the cartridge in alignment with the at least one ventafter insertion of the cartridge into the housing.

In some embodiments, the cartridge may include a duct wall that definesthe central chamber in an interior of the duct wall. The cartridge mayalso include at least one inlet tube defining the at least one inlet,such that the at least one inlet tube may be configured to span betweenthe at least one vent of the housing and the duct wall when thecartridge is inserted within the housing.

In some embodiments of the method, inserting the cartridge into thehousing may define a void between the duct wall and an inner wall of thehousing in fluid communication with an end chamber and the pipe system.The void may only be in fluid communication with the inlet and centralchamber when the sealing member is in the open position. In someembodiments, the cartridge may include an inner duct wall and aconcentric outer duct wall. An interior of the inner duct wall maydefine the central chamber. The at least one inlet opening may bedefined in an outer surface of the outer duct wall, and the at least oneinlet may connect the outer surface of the outer duct wall with thecentral chamber, such that the outer surface of the outer duct wall isin fluid communication with the central chamber. In some embodiments,the cartridge includes a void between the inner duct wall and the outerduct wall in fluid communication with an end chamber and the pipesystem. The void may only be in fluid communication with the inlet andcentral chamber when the sealing member is in the open position.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawings, which are not necessarily drawn toscale, and wherein:

FIG. 1 shows a perspective view of an air admittance valve in accordancewith an embodiment of the present invention;

FIG. 2 shows an exploded view of the air admittance valve of FIG. 1 inaccordance with an embodiment of the present invention;

FIG. 3 shows a perspective view of the air admittance valve of FIG. 1having an open sealing member in accordance with an embodiment of thepresent invention;

FIG. 4 shows a perspective view of the air admittance valve of FIG. 1having a closed sealing member in accordance with an embodiment of thepresent invention;

FIG. 5 shows a perspective view of a cartridge for an air admittancevalve in accordance with an embodiment of the present invention;

FIG. 6 shows a top view of the cartridge of FIG. 5 in accordance with anembodiment of the present invention;

FIG. 7 shows an isometric view of the cartridge of FIG. 5 in accordancewith an embodiment of the present invention;

FIG. 8a shows a cross-sectional view of the air admittance valve of FIG.1 in accordance with an embodiment of the present invention;

FIG. 8b shows a cross-sectional view of the air admittance valve of FIG.1 in accordance with an embodiment of the present invention;

FIG. 9 shows the cross-sectional view of FIG. 8a having the sealingmember in the closed position in accordance with an embodiment of thepresent invention;

FIG. 10 shows a cross-sectional view of the air admittance valve of FIG.1 in accordance with an embodiment of the present invention;

FIG. 11 shows a bottom view of the air admittance valve of FIG. 1 inaccordance with an embodiment of the present invention;

FIG. 12 shows a perspective view of an air admittance valve inaccordance with another embodiment of the present invention;

FIG. 13 shows an exploded view of the air admittance valve of FIG. 13 inaccordance with an embodiment of the present invention;

FIG. 14 shows a perspective view of the air admittance valve of FIG. 13having an open sealing member in accordance with an embodiment of thepresent invention;

FIG. 15 shows a perspective view of the air admittance valve of FIG. 13having a closed sealing member in accordance with an embodiment of thepresent invention;

FIG. 16 shows a perspective view of a cartridge for an air admittancevalve in accordance with an embodiment of the present invention;

FIG. 17 shows a top view of the cartridge of FIG. 17 in accordance withan embodiment of the present invention;

FIG. 18a shows a cross-sectional view of the air admittance valve ofFIG. 13 in accordance with an embodiment of the present invention;

FIG. 18b shows a cross-sectional view of the air admittance valve ofFIG. 13 in accordance with an embodiment of the present invention;

FIG. 19 shows the cross-sectional view of FIG. 19a having the sealingmember in the closed position in accordance with an embodiment of thepresent invention;

FIG. 20 shows a cross-sectional view of the air admittance valve of FIG.13 in accordance with an embodiment of the present invention; and

FIG. 21 shows a bottom view of the air admittance valve of FIG. 13 inaccordance with an embodiment of the present invention.

DETAILED DESCRIPTION

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which some, but not allembodiments of the present invention are shown. Indeed, the presentinvention may be embodied in many different forms and should not beconstrued as limited to the embodiments set forth herein; rather, theseembodiments are provided so that this disclosure will satisfy applicablelegal requirements. Like numbers refer to like elements throughout.

As will be described in greater detail below, the air admittance valve100, 200 according to various embodiments of the present inventionincludes a housing 102, 202, a sealing member 110, 210, and a cartridge120, 220. FIGS. 2 and 13 show exploded views of two embodiments of thepresent invention. In some embodiments, the housing 102, 202 and/orcartridge 120, 220 may be made of a rigid thermoplastic material, suchas, for example, polyvinyl chloride (PVC), acrylonitrile butadienestyrene (ABS), propylene, or fire-rated propylene. In some embodiments,the housing 102, 202 may have a substantially cylindrical shape. In someembodiments, the housing 102, 202 may be curved at a top end and mayhave side walls of varying thickness. It should be noted that in otherembodiments, the housing 102, 202, the cartridge 120, 220, and/or thesealing member 110, 210 may have various other configurations and arenot limited to the shapes and configurations shown in the figures.

In some embodiments the air admittance valve 100, 200 may be assembledby press fit or snap fit assembly that requires no adhesives and/orsonic welding. In some alternative embodiments, the air admittance valve100, 200 may use adhesives and/or sonic welding as an additional oralternative assembly means. The various components of the air admittancevalve 100, 200 may be assembled by inserting the components into thehousing 102, 202 so that the components snap or press into the housingand are frictionally secured in a modular fashion. In some embodiments,the components of the air admittance valve 100, 200 may be removed andreplaced easily because of the frictional attachment. Removable andreplaceable parts can extend the life span of the air admittance valve100, 200, as well as, enhancing the reusability, adjustability, andreparability of the air admittance valve 100, 200. More delicatefeatures of the valves 100, 200, such as the sealing members 110, 210may be removed and replaced to ensure a good seal throughout the life ofthe valve.

Some embodiments of the present invention use vents 104, 106, 204, 206to connect an external environment to the cartridge 120, 220 within thehousing 102, 202. The air admittance valve 100, 200 may use any numberof vents and any number of holes, slots, or other openings for each ventin order to ensure proper airflow into the valve and pipe system. Insome embodiments, each vent 104, 106, 204, 206 may be any shape and mayhave any number of openings capable of allowing air into the inlets 122,124, 222, 224. In some further embodiments, the vents 104, 106, 204, 206may be designed to protect the inside of the valve 100, 200 from debrisor other materials. The vents 104, 106, 204, 206 may be equipped with afilter media, such as a one way screen or other filtering device, inorder to improve the filtering ability of the vents.

In some embodiments, the sealing member 110, 210 includes of a sealingportion 112, 212, which may be limited in its movement by various guidestructures or may float freely within the housing 102, 202. In someembodiments, the sealing member 110, 210 may also include a guidepost114, 214. The guidepost may interact with the housing 102, 202 of theair admittance valve 100, 200, or in some alternative embodiments, theguidepost may interact with the cartridge 120, 220 instead. The guidepost 114, 214 of the sealing member 110, 210 may direct the sealingmember in a substantially linear path between the open and closedpositions. In the open position, the sealing member 110, 210 may moveaway from a sealing structure 128, 228 such that air is allowed to flowfrom the outside environment into the pipe system. In the closedposition, the sealing member 110, 210 may engage the sealing structure128, 228 so as to stop airflow between the pipe system and the outsideenvironment. The sealing structure 128, 228 may be any shape that allowsa seal with the sealing member 110, 210, including, but not limited to,a ring, square, rectangle, torus, bowtie, or any other shapes thatfacilitate a seal. Likewise, the sealing member 110, 210 need not becircular, but may be any complementary shape to the sealing structure128, 228.

The sealing member 110, 210 may be held in a closed position by gravity,and the sealing member may be lifted off of the sealing structure 128,228 into the open position when the pressure differential across thesealing member is enough to overcome the weight of the sealing member.In some embodiments, pressure from the pipe system may also hold thesealing member 110, 210 in the closed position when the pressure in thepipe system is greater than the pressure outside.

Some embodiments of the sealing member 110, 210 may define a supportplate 115, 215 at the interface of the guide post 114, 214 and thesealing portion 112, 212 to secure the attachment between the guide postand the sealing portion, particularly if the sealing portion is made ofa softer material. In some embodiments, the sealing portion 112, 212 maybe overmolded onto the support plate 115, 215 and/or guide post 114,214. In some alternative embodiments, the sealing member 110, 210 may bemade of a single material and/or may be a single contiguous piece.

As will be described in greater detail herein, the cartridge 120, 220may interact with the sealing member 110, 210 to create a one-wayinterface which allows air to travel into the plumbing or pipe systembut not outwardly from the pipe system into the outside environment.Such a system enables the air admittance valve to equalize the pressurein the plumbing system upon discharge of waste while keeping theexterior environment sanitary at the same time.

In some embodiments, the sealing member may be made of a singlematerial, which may be a rigid thermoplastic material, such as, forexample, polyvinyl chloride (PVC), acrylonitrile butadiene styrene(ABS), propylene, fire-rated propylene, or a softer plastic orrubber-like material such as silicone or EPDM rubber. In someembodiments, the sealing member 110, 210 may be made of multiplematerials. For example, a sealing portion 112, 212 of the sealing member110, 210 may be a softer material and the guide post 114, 214 may bemade of a more rigid thermoplastic material. As discussed above, thesealing portion 112, 212, in some embodiments, may be overmolded ontothe guide post 114, 214 and/or the support plate 115, 215. It should beunderstood that sealing member 110, 210 may be made of any material ormaterials that can form a seal with the cartridge.

In some embodiments, the sealing member 110, 210 may be substantiallycircular and may engage a complementary-shaped sealing structure 128,228 on the cartridge 120, 220. The sealing member 110, 210 may engagethe sealing structure 128, 228 with a sealing surface, such as, forexample, with the sealing portion 112, 212 of the sealing member. Insome embodiments, the sealing member 110, 210 may have a partially “V”shaped sealing surface so that it creates a strong seal when coming torest against the sealing structure 128, 228. In some furtherembodiments, as described in greater detail below, the sealing member110, 210 may engage the sealing structure 128, 228 with a sealingsurface and also have a “V” shaped protrusion to provide additionalsupport and engage the center post 146, 294 and/or ribs 148, 150, 152,154, 250, 252, 254, 256 more easily.

In some embodiments, the cartridge 120 is inserted into the bottom orengaging side of the housing 102 such that the entire housing may bemade of a single, contiguous material. Constructing the housing as onesingle piece may allow the assembly to be tamper resistant, in additionto being simpler and less expensive to manufacture.

In some embodiments, the housing 102, 202 may be sufficiently long toconnect directly to a joint of the pipe system where the air admittancevalve is attached, thus saving on piping, pipe cutting, and adhesivecosts. Alternatively, in some embodiments, the housing 102, 202 may beshortened to allow the air admittance valve to fit into tighter spaces.The housing 102, 202 of the air admittance valve 100, 200 may attach tothe pipe system with threading, adhesive, press or snap fit, flexiblecoupling, or any other plumbing attachment means.

FIG. 1 depicts an exterior view of an embodiment of an air admittancevalve 100. The figure shows an exterior view which includes a solidhousing 102 having multiple vents 104, 106 designed to allow air to flowinto the valve 100. In some embodiments, the vents 104, 106 may be madeup of one or more holes in the wall of the housing 102. As describedabove, the housing 102 may be made to any length that fits theapplication of the user. FIG. 2 depicts an exploded perspective view ofthe air admittance valve of FIG. 1 showing the sealing member 110 andthe cartridge 120.

With reference to FIGS. 3-4, in some embodiments, the cartridge 120 hastwo opposite inlets 122, 124 that are disposed within two tubes 123, 125that may connect to a central chamber 170 (e.g. shown in FIG. 8a -10)defined in the center of the cartridge by a central duct wall 168. Asdetailed above with respect to the vents 104, 106, 204, 206, thecartridge 120, 220 may have any number of inlets 122, 124 configured toallow air to flow into the pipe system. In some embodiments, the bottom171 of the central chamber 170 may be curved in order to direct air fromthe inlets 122, 124 upward into the central chamber 170 as shown in FIG.8B. The bottom 171 of the central chamber 170 improve air flow throughthe cartridge by providing a curved surface to direct the flow of airtowards the sealing member 110 from the respective inlets. In someembodiments, the curved surface of the bottom 171 of the central chamber170 may reduce turbulence as the air flows from the multiple inlets 122,124 mix.

When the air admittance valve 100 is assembled, the inlets 122, 124 ofthe cartridge 120 may be configured to align with the vents 104, 106such that the inlets are in fluid communication with an exteriorenvironment. As will be described in greater detail below, a locatingfeature 138 and positioning feature, such as a notch 140 may interactwith the housing 102 to guide and hold the cartridge 120 in alignmentwith the vents 104, 106.

In some embodiments, a pair of gaskets 130, 132 may be configured toseal the cartridge against the wall of the housing 102 such that the airmust be directed into the inlet 122, 124 from the exterior environment.In some embodiments, the gaskets 130, 132 prevent air from leaking intothe pipe system at the interface between the housing and the cartridge.In some embodiments, the air admittance valve 100 may use standardO-rings, washers, or other similar sealing mechanisms as the gaskets130, 132. In some alternative embodiments, adhesives, epoxies, resins,sonic welding, or other sealing means may be used in place of thegaskets 130, 132.

The sealing member 110 may interact with an outlet defined by a sealingstructure 128 at an upper end of the central duct wall 168 to allow airto flow from the central chamber 170 into an end chamber 164 when thesealing member 110 is in an open position as shown in FIG. 3. When inthe open position, in some embodiments, the sealing member 110 movesaway from the sealing structure 128 in order to allow air to flow intothe end chamber 164. In some embodiments, the sealing member 110 maymove into the open position when there is a negative pressure in thepipe system. The sealing member 110 may be held closed by gravity andmay be opened when there is a sufficiently large pressure differentialbetween the exterior environment and the pipe system to overcome theweight of the sealing member.

In some embodiments, the sealing member 110 may be closed when thepressure in the pipe system equals and/or exceeds the pressure in theoutside environment. In this embodiment, odors and other substanceswithin the pipe system cannot escape into the outside environmentbecause the sealing member closes rather than allowing the pipe systemto vent outside. In some embodiments, the air admittance valve isoriented so that the sealing member 110 may be assisted into the closedposition by gravity. In some embodiments, the pressure from the pipesystem holds the sealing member 110 in the closed position when itexceeds the pressure in the outside environment.

In some embodiments, the vents 104, 106, inlets 122, 124, and centralchamber 170 are in fluid communication with the exterior environmentsuch that the pressure inside the central chamber 170 is substantiallythe same as the pressure in the outside environment. Thus, the pressureagainst the lower side of the sealing portion 112 of the sealing member110 may be determined by the exterior environment.

In some embodiments, the end chamber 164 may be in fluid communicationwith the pipe system by a void 182 around the exterior of the cartridgebetween the cartridge 120 and the housing wall. In some embodiments, theupper end of the housing 102 may define a curved top 176 thatencompasses the end chamber 164. The curved top 176 may partially directthe airflow 144 from the central chamber 170 and into the pipe systemwhen the sealing member 110 is in an open position. In some alternativeembodiments, the top of the housing may instead be flat. In someembodiments the pipe system may be in fluid communication with the endchamber 164 the pressure of the air against the top of the sealingportion 112 may be substantially the same as the pressure inside thepipe system. Thus, in some embodiments, the pressure in the pipe systemagainst the top of the sealing portion 112 and the pressure from theoutside environment against the bottom of the sealing member may opposeone another to either open or close the sealing member, depending,respectively, on whether the exterior pressure is greater or less thanthe pressure in the pipe system respectively. FIGS. 3-4 show the sealingmember 110 in the open and closed positions.

With reference to FIG. 5, the cartridge in accordance with variousembodiments of the invention is shown in detail. Inside the centralchamber of the cartridge 170, which is defined by the central duct wall168, there may be multiple ribs 148, 150, 152, 154 which may support thesealing member 110 and help direct airflow through the cartridge 120. Insome embodiments, the center of the central chamber 170 may have acenter post 146. As described in greater detail below, the central post146 and/or the ribs 148, 150, 152, 154 may support the sealing member110 when a positive pressure is exerted on the sealing member from thepipe system so that the sealing member does not collapse into thecentral chamber, thus breaking the seal of the air admittance valve 100.

With reference to FIG. 6, a top view of the cartridge is shown inaccordance with an embodiment of the present invention. Ribs 148, 150,152, 154 can be seen connecting the walls of the central duct wall 168with the central post 146. Any number of ribs may be used in thecartridge depending on the desired air flow and the desired support forthe sealing member 110. In some embodiments, the ribs 148, 150, 152, 154are used to control turbulence and smooth the airflow through the valveassembly 100. Two of the ribs 148, 150 shown in FIG. 6, may lie in thepath of the inlet 122, 124 into the central chamber 170. In someembodiments, the ribs 148, 150, 152, 154 may be placed in the inlets122, 124 or may be designed to avoid the inlets to create the desiredsupport and/or air flow and reduce turbulence caused by the intersectingair streams. With reference to FIG. 7, the edges of the ribs 148, 150placed within the inlets 122, 124 may be tapered or sharpened in orderto improve air flow through the cartridge.

As will be described in greater detail below, the cartridge may alsoinclude locating features 138 that are designed to align and guide thecartridge 120 into and out of the housing 102 in order to ease theassembly process. The locating features 138 may also include a notch 140or other similar positioning feature that enables the cartridge to besecured at a desired position within the housing, i.e., by interactingwith a corresponding notch or positioning feature in the housing.

FIG. 8a -10 show cross-sectional views of the air admittance valve 100in accordance with various example embodiments of the present invention.In the embodiments shown in FIG. 8a -10 features such as the vents 104,106 may have portions removed for exemplary purposes; however, in someembodiments, the vents 104, 106 have openings across a majority of thesurface area of the inlets 122, 124. FIG. 8a shows a centralcross-section of the valve 100 having a cartridge 120 in accordance withan embodiment of the present invention, such that the ribs 148, 150 inthe inlet are shown as well. In some embodiments, entering air flow 142travels into the inlets 122, 124 through inlet openings 156, 158 whichmay be placed adjacent to the vents 104, 106 in the housing 102, whenthe cartridge is in position. The air flow 142 enters the inlet openingand travels into the central chamber 170 and upward into the end chamber164. In some embodiments, the sealing member 110 is made up of a sealingportion 112 and a guide post 114 as shown in FIG. 8a . The guide postmay interact with a hollow seal guide 160 in the housing top 176 thatmay limit the motion of the sealing member 110 to a single verticalaxis. In some embodiments, and as shown in FIG. 8a , the hollow sealguide 160 may be a complementary shape to the guide post 114, such as,for example, a cylinder. In some embodiments, the guide may be supportedby substantially triangular struts 162. In some alternativeenvironments, the guide post may be attached to the housing and thehollow guide may be disposed on the sealing member.

As detailed above, in some embodiments, the sealing portion 112 of thesealing member 110 may be made of a soft material to enable a betterseal between the sealing member 110 and the sealing structure 128. Insome embodiments, the guide post 114 may be made of a more rigidmaterial than the sealing portion to enable smoother communicationbetween the guide post 114 and the hollow guide 160 and may be made of aharder plastic or similar material.

FIG. 8b shows an embodiment of the air admittance valve 100 shown inFIG. 8a where the cross-section is offset so that the ribs disposedwithin the inlets 122, 124 are not visible. The air flow entering thecartridge may travel from the inlet opening 156, 158 into the centralchamber 170 and out the outlet of the central chamber into the endchamber 164.

As previously discussed, a pair of gaskets 130, 132 may be disposedaround the junction between the cartridge and the housing such that airis not allowed to escape between the cartridge and the housing into thepipe system. In some embodiments, the gaskets 130, 132 may be held inplace by corresponding slots 131, 133 in the cartridge and/or in thehousing 102. In some embodiments, these slots 131, 133 may be positionedaround the inlet openings 156, 158 and may hold the gaskets 130, 132 inplace.

In some embodiments, an internal communication wall 134 may bepositioned at or near one end of the cartridge 120 to align thecartridge within the housing 102 and aid in controlling the flow of airthrough the air admittance valve. The internal communication wall 134may assist with aligning the cartridge 120 with the housing 102 duringinstallation. In some embodiments, the internal communication wall 134may allow air to flow freely from the end chamber to the pipe systemaround the tubes 123, 125 which contain the inlets 122, 124. In someembodiments, the air may travel in the void 182 between the cartridgeand the housing 102 with the air flow path 144 created by thecombination of the housing 102 and the cartridge 120. In someembodiments, the internal communication wall 134 may use holes oropenings as a mesh-like surface in order to protect the inside of thevalve 100 from debris or other materials. In some alternativeembodiments, the internal communication wall 134 may have wider openingsor the cartridge 120 may not have an internal communication wall.

With reference to FIG. 10, a cross-section of an embodiment of the airadmittance valve 100 is shown at a ninety degree angle to thecross-sections shown in FIG. 8a and FIG. 8b . In the cross section ofthis embodiment, the locating features 138 are shown having the notches140 engaging with the wall of the housing 102.

FIGS. 3 and 8 a show views of an embodiment of the air admittance valve100 showing the air paths 142, 144 through the valve. The entering air142 may travel through the inlets 122, 124. The air 142 is then directedinto the central chamber 170, where the pressure within the centralchamber and the corresponding negative pressure in the end chamber 164opens the sealing member 110 and allows the exiting air 144 to flow intothe end chamber 164. Once inside the end chamber 164, the air travelsaround the cartridge and down into the pipe system. In the embodimentshown in FIG. 3 the exiting airflow 144 travels in the void 182 betweenthe central duct wall 168 and the housing 102.

FIG. 11 shows a bottom view of an embodiment of the present invention.In FIG. 11, the housing 102 may have numerous slots and cutaways 172,174 that help direct and hold the cartridge 120 and the sealing member110 in the correct positions within the valve assembly 100. The locatingfeature 138 may travel in a locating slot 172 until the notch 140 orother positioning feature engages with a corresponding positioningfeature 141 (shown in FIG. 10) in the housing 102. Likewise, the inletopenings 156, 158, which are connected to the tubes 123, 125 may fitinto slots or deformations 174 in the housing 102 which help to guideand align the cartridge 120 within the housing 102. In some embodiments,the slots 172, 174 may help align the rotational position and axialposition of the cartridge 120 and particularly the inlet openings 156,158 with the vents 104, 106 in the housing 102. The locating feature138, in some embodiments, may include a lock or locking mechanism to atleast partially prevent disassembly of the air admittance valve 100.

In some embodiments of the present invention, the internal wall 180 ofthe housing 102 may be tapered so that the diameter of the housingdecreases the closer the cartridge 120 gets to its final position. Atapered housing 102 may allow the cartridge to be held more firmly inthe housing, while at the same time easing the assembly process andensuring the gaskets 130, 132 stay in position. The tapered housing 102may additionally or alternatively assist with a molding process bymaking the housing easier to remove from a mold. In some embodiments,the tapered housing 102 may allow the housing to engage a standard pipesize at a bottom end and still allow the cartridge 120 to slide into andrest in the top end. In the embodiments in which the housing 102 is usesthreading to engage the pipe system, the internal diameter of thehousing may be sufficiently wide at the threaded end, due to the taper,that the cartridge 120 does not catch on the threads during assembly. Insome embodiments, there may be a stopper or lip that limits the verticalmovement of the cartridge 120. In some embodiments, the slots 172, 174may naturally terminate at the correct cartridge 120 position in thehousing 102. In some embodiments, the notch 140 or other similarpositioning feature may allow the cartridge 120 to snap into and be heldin the proper vertical and angular positions.

In some embodiments, the cartridge 120 is positioned within the housing102 to allow the sealing member 110 to operate properly. Someembodiments of the sealing member 110 must be allowed to move betweenthe open and closed positions while, at the same time, not separatingthe guide posts 114 from the hollow guide 160. A lip and/or taper may beconfigured to hold the cartridge 120 at a desired distance from the topof the housing 176.

With reference to FIG. 12, another embodiment of the present inventionis shown. FIG. 12 depicts an exterior view of the housing 202 of an airadmittance valve 200. The housing 202, in some embodiments, may have aplurality of vent slots 204, 206 that allow air into the pipe systemfrom the exterior environment. In some embodiments, vents 204, 206 maybe slot-shaped with elongate vertical or horizontal openings. Asdetailed above, the housing 202 may have a substantially cylindricalshape, and may have a curved top and/or variations in the thickness ofthe walls of the housing. In some embodiments, the housing 202 may havea series of stepped ridges along its outer surface. Some embodiments ofthe housing 202 of the air admittance valve 200 may have a varying wallthickness in order, for example, to minimize manufacturing costs whilemaintaining the strength of the valve at key structural locations. Thehousing 202 may have a varying or tapered thickness in order to easeremoval from a mold and/or to ease the assembly process by allowing thecartridge to slide unimpeded through the lower section of the housing.In some embodiments, the housing 202 may vary in thickness to allow thebottom of the housing to engage a standard pipe size while the top ofthe housing may be shaped to accommodate standard size gaskets 230, 232(e.g. standard size O-Rings) around the cartridge 220. In theembodiments in which the housing 202 is uses threading to engage thepipe system, the internal diameter of the housing may be sufficientlywide at the threaded end, due to the taper or varied thickness, that thecartridge 220 does not catch on the threads during assembly. Also asdetailed above, the housing 202 may be longer or shorter as needed bythe user to couple with the pipe system. FIG. 13 depicts an explodedperspective view of the embodiment of the air admittance valve 200 ofFIG. 12 showing the sealing member 210 and the cartridge 220.

FIGS. 14-15 illustrate a housing 202, sealing member 210 and cartridge220 in accordance with some embodiments of the present invention. In theembodiment shown in FIGS. 14-15, the cartridge 220 has two oppositeinlets 222, 224 that enter the side of the cartridge and a centralchamber 270 within a central duct wall 268. In some embodiments,however, the cartridge 220 may have any number of inlets. The sealingstructure 228 of the cartridge 220 may engage a sealing member 210 inorder to create a one-way valve configuration. As detailed above, thesealing member 210 may include a sealing portion 212 in some embodimentsand, in some further embodiments, may include a guide post 214. In someembodiments, the sealing member 210 may be closed when the pressure inthe pipe system equals and/or exceeds the pressure in the outsideenvironment. In this embodiment, odors and other substances within thepipe system cannot escape into the outside environment because thesealing member closes rather than allowing the pipe system to ventoutside. In some embodiments, the air admittance valve is oriented sothat the sealing member 210 may be assisted into the closed position bygravity. The pressure from the pipe system may hold the sealing member210 in the closed position when it exceeds the pressure in the outsideenvironment. In some embodiments, the cartridge may have multipleconcentric duct walls 238, 268 which allow air to flow between themafter traveling between the open sealing member 210 and the sealingstructure 228.

In the embodiments shown in FIG. 14-15, when the sealing member 210 isin an open position, entering air 244 flows into the inlets 222, 224 viathe vents 204, 206 in the housing 202, through the central chamber 270into the end chamber 264 of the air admittance valve 200, and down intothe pipe system. In some embodiments, the cartridge 220 may have twoconcentric duct walls 238, 268 with a void therebetween. In someembodiments, the inlets 222, 224 pass through the outer duct wall 238and through the central duct wall 268 to allow air to flow directly fromthe exterior environment to the central chamber 270. In someembodiments, the void 292 between the central duct wall 268 and theouter duct wall 238 may allow the end chamber 264 to be in fluidcommunication with the pipe system. In the embodiment shown in FIGS.14-15, the airflow 246 exiting the central chamber passes through thevoid 292 between the outer 238 and central duct wall 268 of thecartridge 220. Some embodiments may use support structures 240 betweenthe central duct wall 268 and the outer duct wall 238. Some furtherembodiments may use a mesh or similar structure between the two ductwalls 238, 268.

As described above, in some embodiments, the inlets 222, 224 and thecentral chamber 270 are in fluid communication with the outsideenvironment, such that their pressures substantially match that of theoutside environment. Likewise, in some embodiments, the end chamber 264,the void 292, and the pipe system are also in fluid communication, suchthat the pressure in the end chamber 264 substantially matches that ofthe pressure in the pipe system. Thus, in some embodiments, when thepressure in the exterior environment, and thus in the central chamber270, is greater than the pressure in the pipe system, and thus the endchamber 264, the sealing member 210 is moved into an open position toallow the pressures to substantially equalize. As described above, insome embodiments, when the pressure in the pipe system is greater thanthe pressure in the exterior environment, the sealing member is held ina closed position, such as in the embodiment shown in FIG. 15.

In some embodiments, the upper end of the housing 202 may define acurved top 290 that encompasses the end chamber 264. The curved top 290may partially direct the airflow 244 from the central chamber and intothe pipe system when the sealing member 210 is in an open position. Insome alternative embodiments the upper end of the housing 202 mayinstead be flat.

With reference to FIGS. 16-17, in some embodiments, the cartridge mayhave multiple ribs 250, 252, 254, 256 that direct air flow through thecentral chamber 270, as well as support the sealing member 210 and thestructure of the cartridge 202. The cartridge 202 may also have a centerpost 294, in some embodiments, that is configured to support the sealingmember 210 in the event of a positive pressure from the pipe system. Insome embodiments, one or both of the center post 294 and the ribs 250,252, 254, 256 may support the sealing member 210 and prevent it frombeing pushed into the central chamber by gravity and/or the pressure inthe pipe system.

In some embodiments, the bottom 271 of the central chamber 270 may becurved in order to direct air from the inlets 222, 224 upward into thecentral chamber 270 as shown in FIG. 17. The bottom 271 of the centralchamber 270 improve air flow through the cartridge by providing a curvedsurface to direct the flow of air towards the sealing member 210 fromthe respective inlets. In some embodiments, the curved surface of thebottom 271 of the central chamber 270 may reduce turbulence as the airflows from the multiple inlets 222, 224 mix.

FIG. 18a -20 show cross-sectional views of the air admittance valve 200in accordance with various example embodiments of the present invention.In the embodiments shown in FIG. 18a -20 features such as the vents 204,206 may have portions removed for exemplary purposes; however, in someembodiments, the vents 204, 206 have openings across a majority of thesurface area of the inlets 222, 224. As shown in FIG. 18a , the centralpost 294 of the cartridge 220 is located in line with the travel path ofthe sealing member 210. As discussed above, if a positive pressure isplaced on the sealing member 210, the central post 294 and/or the ribs250, 252, 254, 256 may prevent the sealing member 210 from collapsinginto the central chamber 270. In some embodiments, the central post 294may be positioned to contact the sealing member 210 whenever the sealingmember is in a closed position. In some other embodiments, the sealingmember 210 may be spaced a small distance from the central post 294,such that the central post only contacts the sealing member 210 when apositive pressure is applied.

In some embodiments, pair of gaskets 230, 232 may be disposed around thejunction between the cartridge and the housing such that air is notallowed to escape between the cartridge and the housing into the pipesystem. In some embodiments, the gaskets 230, 232 may be held in placeby corresponding slots 231, 233 in the cartridge and/or in the housing102. In some alternative embodiments, the gaskets 230, 232 may rest onupward-facing surfaces of the cartridge 220 so that the insertion of thecartridge into the housing 202 forms a compression seal. In someembodiments, the gaskets 230, 232 may be positioned concentricallyaround the outer duct wall 238 above and below the inlets 222, 224 suchthat air may not flow into the pipe system or end chamber 264 withouttraveling through the central chamber 270. In the embodiments shown inFIGS. 14-15, the gaskets 230, 232 are concentric with the duct walls238, 268 and prevent air from flowing around the outer duct wall andinto the pipe system in order to create the pressure differential andforce air to act on the sealing member 210. In some embodiments, the airadmittance valve 200 may use standard O-rings, washers, or other similarsealing mechanisms as the gaskets 230, 232. In some alternativeembodiments, adhesives, epoxies, resins, sonic welding, or other sealingmeans may be used in place of the gaskets 230, 232.

With reference to FIG. 18b , a cross-section is shown where thecross-section is taken offset from a center line of the housing andcartridge, such that the ribs 150, 152 disposed within the inlets 222,224 are not shown. In some embodiments, there may not be ribs disposedwithin the inlets 224, 224 depending on the desired support and/or airflow through the cartridge 220. In some alternative embodiments, theribs 250, 252 may be positioned in the inlets 222, 224 in order toreduce turbulence of the air flowing into the cartridge.

With reference to FIG. 19, a cross-section of the air admittance valve200 is shown in accordance with an embodiment of the present inventionthat has support structures 240 (as shown in FIGS. 16-17) extendingbetween the outer duct wall 238 and the central duct wall 268. As shownand described above, the end chamber 264 may be in fluid communicationwith the pipe system because of the void 292 between the outer 238 andcentral 268 duct walls.

As discussed above, the side walls of the housing 202 may also betapered or stepped in order to ease assembly and/or molding, forexample, so that the cartridge 220 does not engage the housing until itis close to the proper alignment (thus reducing wear on the gaskets 230,232), or the housing may be able to slide off a mold easier. In someembodiments, the housing 202 may be have a more defined, tapered section242 in order to axially position the cartridge 220 within the housing.The cartridge 220 may have a corresponding taper. In some embodiments,the housing 202 may have a lip 288 that restricts the axial movement ofthe cartridge within the housing. The purpose of the tapering 242 and/orlip 288 features is to ensure axial alignment of the vents 202, 204 andthe inlets 222, 224, as well as to ensure proper operation of thesealing member 210. The sealing member 210 must allowed to freely movebetween the open and closed positions while, at the same time, notdislodging the guide posts 214 from the hollow seal guide 260. The lip288 and/or taper 242 may be configured to hold the cartridge 220 at adesired distance from the top of the housing 290. As described above, insome embodiments, the housing may interact with the cartridge via one ormore gaskets 230, 232.

In some further embodiments, the cartridge 220 is tapered so that itcorresponds to the taper 242 in the housing 202 and one end of thecartridge has a smaller diameter than the other. The cartridge 220 maybe tapered such that it is held at a predetermined distance from the endof the housing 290. In some embodiments, upper gasket 230 of thecartridge has a narrower diameter, corresponding to the taper, than thelower gasket 232. The upper gasket 230 may additionally or alternativelyhave a narrower diameter so that the gasket does not contact the vents204, 206 as the cartridge 220 is inserted into the housing 202. Asdescribed above, in some embodiments, the housing may have an inner 286and an outer 284 wall. The inner wall may taper inward the closer thecartridge 220 gets to the top of the housing 290, such that thecartridge 220 is easy to insert into the housing 202, but remains inposition once inserted.

In some embodiments, the cartridge 220 may be further configured withpositioning features, such as, for example, alignment bumps 234, 236that help to position and align the cartridge 220 when it is insertedinto the housing. As shown, for example, in FIG. 18a-18b , one or moreof the positioning features 234, 236 may engage with one or morecorresponding positioning features in the housing to hold the cartridge220 in a desired axial position. For example, as shown in FIG. 18a-18b ,the lower positioning feature 236 engages a corresponding positioningfeature, such as a groove in the housing 202, while the upperpositioning feature 234 rests against the inner wall 286 of the housing.The one or more corresponding positioning features may engage one ormore of the positioning features 234, 236 to lock the cartridge 220 in adesired position to facilitate a snap-fit assembly.

Additionally or alternatively, the cartridge 220 may have one or morelocating features, such as, for example, alignment tabs 296 that mayposition the cartridge rotationally and/or axially within the housing.As shown in FIGS. 13-19, one or more tabs 296 may protrude from the topof the cartridge and engage corresponding slots 298 in the housing. Theslots 298 may be adjacent to the lip 288 such that the tabs 296rotationally and axially hold the inlets 222, 224 in alignment with thevents 204, 206 of the housing 202. In some embodiments, the tabs 296 mayadditionally or alternatively have locking features that engage thehousing 202 to resist removal of the cartridge 220 from the housing.

FIGS. 14 and 18 a show views of an embodiment of the air admittancevalve 200 showing the air paths 244, 246 through the valve. In theembodiment shown in FIG. 18a , the entering air 244 may travel throughthe inlets 222, 224. The air may then be directed into the centralchamber 270, where the pressure difference between the central chamberand the end chamber 264 opens the sealing member 210 and allows theexiting air 246 to flow into the end chamber 264. Once inside the endchamber 264, the air may travel through the cartridge and down into thepipe system. In the embodiment shown in FIG. 14 the exiting airflow 246travels in the void 292 between the central duct wall 268 and the outerduct wall 238.

FIG. 21 shows a bottom view of the air admittance valve 200, inaccordance with an embodiment of the present invention. In someembodiments, the bottom of the central duct wall 268 may have a shaft280 corresponding with the central post 294, to lighten and reducematerial costs for manufacturing the central shaft. The shaft 280 mayalso have one or more slots 282 to aid with alignment and positioning ofthe cartridge 220 during assembly. In some embodiments, the shaft 280and/or slots 282 may facilitate removal of the cartridge 220 duringdisassembly, such as, for example, by being tapped or threaded to allowthe cartridge to be pulled outward from the housing.

As a result, and among other benefits, the present invention improvesthe air admittance valve design by providing an air admittance valve100, 200 having a modular, tamper-resistant, repairable, durable, easyto manufacture design with improved performance.

Many modifications and other embodiments of the invention set forthherein will come to mind to one skilled in the art to which thisinvention pertains having the benefit of the teachings presented in theforegoing descriptions and the associated drawings. Therefore, it is tobe understood that the invention is not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purpose of limitation.

What is claimed is:
 1. A cartridge for an air admittance valvecomprising: at least one inlet defining at least one inlet opening,wherein the at least one inlet is connected to a central chamber; anopening of the central chamber having a sealing structure; wherein thesealing structure of the cartridge is configured to interact with asealing surface of a sealing member to allow one-way airflow from thecentral chamber to the pipe system; wherein the cartridge is configuredto be disposed within a housing having at least one vent, such that theat least one inlet opening of the cartridge is configured tosubstantially align with the at least one vent in the housing.
 2. Thecartridge of claim 1, further comprising: at least one gasket configuredto be disposed between the cartridge and the housing to prevent airflowfrom bypassing the inlet of the cartridge.
 3. The cartridge of claim 1,further comprising: an internal communication wall configured to alignthe cartridge with an interior of the housing, wherein an end chamber isdefined between the cartridge and a second end of the housing when thecartridge is disposed within the housing, and wherein the internalcommunication wall defines at least one opening such that the internalcommunication wall is configured to fluidly connect the end chamber withthe pipe system.
 4. The cartridge of claim 1, further comprising: acentral post within the central chamber configured to restrict themovement of the sealing member into the central chamber when subjectedto a positive pressure from the pipe system.
 5. The cartridge of claim1, further comprising: a locating feature on the cartridge configured toengage a corresponding locating slot on the housing and configured toguide the cartridge into alignment with the at least one vent duringinsertion of the cartridge into the housing.
 6. The cartridge of claim1, further comprising: a positioning feature on the cartridge configuredto engage a corresponding positioning feature on the housing andconfigured to hold the cartridge in alignment with the at least one ventafter insertion of the cartridge into the housing.
 7. The cartridge ofclaim 1, wherein the cartridge further comprises: a duct wall thatdefines the central chamber in an interior of the duct wall; and atleast one inlet tube defining the at least one inlet, such that the atleast one inlet tube is configured to span between the at least one ventof the housing and the duct wall when the cartridge is inserted withinthe housing.
 8. The cartridge of claim 7, wherein the cartridge isconfigured to define: a void between the duct wall and an inner wall ofthe housing in fluid communication with an end chamber and the pipesystem when the cartridge is inserted into the housing, and wherein thevoid is only in fluid communication with the inlet and central chamberwhen the sealing member is in the open position.
 9. The cartridge ofclaim 8, wherein the cartridge further defines an inner duct wall and aconcentric outer duct wall, wherein an interior of the inner duct walldefines the central chamber, wherein the at least one inlet opening isdefined in an outer surface of the outer duct wall and the at least oneinlet connects the outer surface of the outer duct wall with the centralchamber, such that the outer surface of the outer duct wall is in fluidcommunication with the central chamber.
 10. The cartridge of claim 9,further comprising: a void between the inner duct wall and the outerduct wall configured to be in fluid communication with an end chamberand the pipe system when the cartridge is inserted into the housing, andwherein the void is only in fluid communication with the inlet andcentral chamber when the sealing member is in the open position.
 11. Thecartridge of claim 1, wherein the cartridge further defines at least onecurved surface configured to direct airflow from the at least one inlettoward the sealing member.
 12. The cartridge of claim 11, wherein the atleast one curved surface is defined on a bottom surface of the centralchamber proximate the at least one inlet.
 13. A method for assembling anair admittance valve comprising: providing a housing configured toengage a pipe system at a first end having at least one vent disposed ina wall of the housing; inserting a sealing member having a sealingsurface into the housing; and inserting a cartridge having at least oneinlet defining at least one inlet opening into the housing, such thatthe at least one inlet opening substantially aligns with the at leastone vent in the housing; wherein the at least one inlet is connected toa central chamber having an opening defining a sealing structure; andwherein the sealing surface of the sealing member is configured tointeract with the sealing structure of the cartridge to allow one-wayairflow from the central chamber to the pipe system.
 14. The method forassembling the air admittance valve of claim 13, wherein the sealingmember further comprises a guide portion and the housing further definesa seal guide; and wherein the seal guide is configured to movably engagethe guide portion.
 15. The method for assembling the air admittancevalve of claim 13, further comprising: locating at least one gasketbetween the cartridge and the housing to prevent airflow from bypassingthe inlet of the cartridge.
 16. The method for assembling the airadmittance valve of claim 13, wherein the cartridge further comprises:an internal communication wall configured to align the cartridge with aninterior of the housing, wherein an end chamber is defined between thecartridge and a second end of the housing when the cartridge is disposedwithin the housing, and wherein the internal communication wall definesat least one opening such that the internal communication wall isconfigured to fluidly connect the end chamber with the pipe system. 17.The method for assembling the air admittance valve of claim 13, whereinthe cartridge further comprises: a central post within the centralchamber configured to restrict the movement of the sealing member intothe central chamber when subjected to a positive pressure from the pipesystem.
 18. The method for assembling the air admittance valve of claim13, wherein the cartridge further comprises: a locating feature on thecartridge configured to engage a corresponding locating slot on thehousing and configured to guide the cartridge into alignment with the atleast one vent during insertion of the cartridge into the housing. 19.The method for assembling the air admittance valve of claim 13, whereinthe cartridge further comprises: a positioning feature on the cartridgeconfigured to engage a corresponding positioning feature on the housingand configured to hold the cartridge in alignment with the at least onevent after insertion of the cartridge into the housing.
 20. The methodfor assembling the air admittance valve of claim 13, wherein thecartridge further comprises: a duct wall that defines the centralchamber in an interior of the duct wall; and at least one inlet tubedefining the at least one inlet, such that the at least one inlet tubeis configured to span between the at least one vent of the housing andthe duct wall when the cartridge is inserted within the housing.
 21. Themethod for assembling the air admittance valve of claim 20, whereininserting the cartridge into the housing defines a void between the ductwall and an inner wall of the housing in fluid communication with an endchamber and the pipe system, and wherein the void is only in fluidcommunication with the inlet and central chamber when the sealing memberis in the open position.
 22. The method for assembling the airadmittance valve of claim 21, wherein the cartridge further defines aninner duct wall and a concentric outer duct wall, wherein an interior ofthe inner duct wall defines the central chamber, wherein the at leastone inlet opening is defined in an outer surface of the outer duct walland the at least one inlet connects the outer surface of the outer ductwall with the central chamber, such that the outer surface of the outerduct wall is in fluid communication with the central chamber.
 23. Themethod for assembling the air admittance valve of claim 23, wherein thecartridge further defines: a void between the inner duct wall and theouter duct wall in fluid communication with an end chamber and the pipesystem, and wherein the void is only in fluid communication with theinlet and central chamber when the sealing member is in the openposition.